Electrolytic apparatus



G. 0. SEWARD.

ELECTROLYTIC APPARATUS. l APPLICATION FILED OCT. Il, 1917 RENEWED MAY 3,192l.

" l 548,141, Patented Fb'. 2s, 1922.

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` By llomeys,

UNITED STATES PATENT OFFICE.

GEORG-E 0. SEWARD, OF NIAGARA FALLS, NEW YORK, ASSIGNOR T0 AMERICAN MAG-NESIUM CORPORATION, 0F NIAGARA FALLS,

TION 0F NEW YORK.

NEW YORK, A CORPORA- Application led October 11, 1917, Serial No. 196,026. Renewed May 3,

To all whom it may concern.'

Be it known that I, GEORGE O. SEWARD, a citizen of the United States of America, residing in Niagara Falls, in the county of Niagara, State of New York, have invented certain new and useful Improvements in Electrolytic Apparatus, of which the following is a specification.

, This invention provides an electrolytic furnace adapted for electrolyzing a bath of molten salts, orcompounds, for example, of haloid salts; and particularly salts of metals which are lighter than the molten bath, so that upon being electrode osited, or separated, the metal rises throng the bath and'floatsy upon the top of theelectiolyte.

vThe apparatus is designed especially for use in practicing a process for electrodepositing magnesiumwhich is set forth in another application for patent which I have prepared and which is intended to be filed concurrently, or substantially so, with the present application, filed November 191917, patented July 22, 1919, No. 1,310,450.

In a prior United States Patent No. 880,489,

atentef February 25, 1908 toFranz von ugelgen and George O. Seward, there is described and claimed an electrolytic process of producing magnesium or alloys thereof, according to which magnesium oxid is added to a molten bath containing magnesium fluorid and a fluorid of a metal or metals electropositive to magnesium. M present invention relates to apparatus adapted to performing operations ofthe' above general character.

Fig. 1 of the accompanying drawing is a transverse section of the preferred construction of an electrolytic furnace according'to the resent invention.

Fig. 2 is a plan of the furnace on a smaller scale.

In the drawings, 1 represents' a metallic vessel or container kfor the bath, which is preferably an unlined, rectangular vessel of cast iron or other suitable metal, preferably supported upon blocks 2 in such manner as to afford av free circulation of'air beneath the vessel in order to avoid overheating. The bath solidifieslto a greater or lesser extent around the walls and upon the bottom, as indicated at 3, a central portion or pool 4 remaining fluid under the operating conditions. consist of a eavy plate of cast ironor other Specification of Letters Patent.

5 replresents the cathode which may Patented Feb. 28, 1922.4 1921. Serial 111,468,531.

metal extending longitudinally of the vessel and projecting verticall through an. aperture 6 in its bottom. Yhe` cathode may be provided with a water-cooled base 7. The temperature at the bottom of the vessel is such that the solidified bath sets around thebase of the cathode, rendering any material leakage .at this point impossible. Cooling-coils 8 may be provided in order to render this closure positive under all operating conditions. The upper edge ofthe cathode may be beveledas indicated in order to facilitate the upward flow and detachment of the molten magnesium.

9, 9 represent the anodes which may be of carbon `or graphite, illustrated in Fig. 1 as depending into the bath upon either side of the cathode, and out of vertical alinement therewith. Any desired or suitable number of anodes may be provided. 10 indicates a layer of magnesium oxid or of magnesium carbonate floating upont-he surface of the bath and serving not only to retain the heat but also as a primary source of raw material for the production of magnesium, the magnesium oxid either dissolving progressively in the bath and undergoing electrol sis therein, or uniting with fluorin liberate by the current and hence restoring the magnesium fluorid content ofthe bath. In case magnesium carbonate is used it is eventually converted into magnesium oxid by calcination in situ. Eit magnesium carbonate is effective to protect the anodes, which are otherwise subject to strong attack ator near the surface of the bath.

11 are indicated near .the surface of the bath on either side of the cathode, above its upper edge. The purpose of these is to chill and thereby to solidify a limited portion of the surface area of the bath as clearly indicated in Fig. 1,'the crust thus formed' shielding the floating metal from the atm here but being readil broken through w en the metal is to be co lected.

The process to be racticed with this construction. of electro ytic-cell or furnace .is fully set forth in my companion application abovereferred to. Suffice it here to say that for the production of magnesium, the bath or electrolyte should be composed of owing-pipes er magnesium oxid or suitable fluorids, such that the molten bath l lals the produced magnesium to rise constantly to the surface. This bath is maintained molten by a suitable current, a temperature of 900 to 1000o C. being foundsuitable. At the same time a sufficient flow`of water is maintained through the cooling pipes and jacket 7 to insure an incrustation of congealed salt around these pipes and where the cathode passes through the bottom or` the tank. As the source of heat is between the electrodes, no diliculty is experienced in maintaining the layer 3 of incrusted salt as alining for the tank itself. The layer 10 of magnesium oxid or carbonate is replenished from time to time.v The bath of molten magnesium accumulates within the chamber formed by the incrustation' surrounding the pipes 11, until it reaches sufficient volume to make it desirable to remove it, when the molten metal is ladled out, or otherwise removed. It is found in practice that this can be 'done without a material loss of magnesium by burning.

The anodes are best arranged so that they vmay be individually fed downwardly into the electrolyte as they are oxidized and consumed. For this purpose, they are carried by rods 12, suitably connected to them and suitably fastened to bus-bar 13. The clamping and adjusting means are not shown, as l suchmeans are well known in the art.

The use of separately adjustable anodes depending into the electrolyte and surrounded thereb is practically necessary, so that they can be fed down from'. time to time as required without interfering with the continuous operation of the furnace; whereas if the furnace were constructed with an anode lining as set forth in U. S. Patent No. 864,928, this lining would eventually be eaten away where it'contacts with the electrolyte, and particularly at the surface of the bath, and this after a time would require that the operation of'the furnace be discontinued while renewing this anode linit will be obvious that the proportions and arrangement may be considerably varied according to circumstances, and Within the skill and judgment of those skilled in this art without departing from the invention.

lliVhat I claim is:

1. lAn electrolytic apparatus for producing .a metal lighter than the electrolyte, comprising a vessel for containing a molten fluorid bath, having its walls so remote from the electrodes as to maintain an insulating layer of congealed salt thereon, a. cathode projecting upwardly through such layer into the vessel, independently adjustable anodes .depending into the vessel out of vertical ahnement with the cathode, and means for cooling the upper portion of the bath, located to separate thev portion above the cathode from the portion surrounding the anodes whereby to form, by a local solidification of the bath, an enclosure for receiving the molten light metal which rises from the cathode. Y

2. An electrolytic apparatus for producing a metal lighter than the electrolyte, comprising a vessel for containing a molten luorid bath, having its walls so remote from the electrodes as to maintain 'an insulating layer of congealed salt thereon, a cathode projecting upwardly through such layer into the central portion of the vessel, independently adjustable anodes depending into the vessel on opposite sides of the cathode and out of vertical alinement therewith, and means for cooling the upper portion of the bath, located to separate the portion above i the cathode from the portion surrounding the anodes whereby to form, by a local solidiication of the bath, an enclosure for receiving the molten light metal which rises from the cathode. l

3. An electrolytic apparatus according to claim 1, the chamber above the cathode formed by such coolingmeans covered over and adapted to receive the separated light metal, and the space overlying the electrolyte surrounding the anodes adapted to receive a layer of material floating on the electrote. 4. An electrolytic apparatus for producing a metal lighter than the electrol e, comprising a vessel for containing a mo ten bath, having Aits walls so remote from the electrodes as to maintain an insulating layer of congealed salt thereon, a cathode, anodes depending into the bath and out of vertical alinement with the cathode, and means for cooling the upper portion of the bath l0- cated to separate the portion above the cathode from the portion surroundin the anodes, whereby to form by a local so idification of the bath, anenclosure for receiving the molten light metal which rises -from the cathode.

v5. An electrol tic ap aratus according to claim 4, the enclosure ibrmed by such cooling means being covered over and ada ted to receive" the separated light metal, an the space overlying the electrolyte surrounding the anodes adapted to receive a layer of material floating on the electrolyte.

6. An electrolytic apparatus for producing a metal lighter than the electrolyte, comprising a vessel 'for containing a lmolten bath and having on its walls a layer of congealed bath material, a cathode and an anode, and means for cooling a portion of the bath located between the said anode and cathode to provide an enclosure,d the said enclosure being covered over with a layer of incrusted material.

7. An electrolytic ap aratus for producing ametal lighter t an the velectrol bath and having on its walls a layer of congealed bath material, a cathode, and an anode, and means for cooling a portion of the bath located between'the said anode and cathode to provide an enclosure, the said enclosure being covered over With a layer of incrusted material and the space overlying the electrolyte surrounding the anodes adapted to receive a layer of material floating on the electrolyte.

8. An electrolytic apparatus for producing a metal lighter than the electrolyte, com.- prising a vessel for containing a molten bath and havin on its side Walls a layer of congealed bat material, means for cooling a portion of the bath remote from-said Walls to provide a barrier of con ealed bath material, and a covering of sohd metalliferous prlsing a vessel for containing a molten bath, an anode and a cathode area of bath,

cooling means interposed between the said i areas to form-a local solidifcation of the bath, the cathode area being covered over with incrusted material and adapted to receive the separated light metal and the anode area adapted to receive a layer of material floating on the electrolyte.

vInwitness whereof, I have hereunto signed my name.

GEORGE o. SEWARD. 

